[Special tumor entities in the head and neck region: nasopharyngeal, salivary gland, and thyroid cancer]. / Spezielle Tumorentitäten im Kopf-Hals-Bereich: Nasopharynxkarzinom, Speicheldrüsenkarzinom und Schilddrüsenkarzinom.

BACKGROUND: At the meetings of the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) in 2022, studies were presented which suggest changes in the clinical routine of nasopharyngeal, salivary gland, and thyroid cancer. OBJECTIVE: Therapeutic innovations for special otorhinolaryngological tumor entities with potential clinical relevance were assessed after reviewing the studies presented at the ASCO 2022/ESMO 2022 meetings. MATERIALS AND METHODS: The presented clinical phase II and phase III studies were analyzed. Results were classified according to their potential clinical importance, taking into account current treatment standards. RESULTS: Three studies were presented that dealt with the topic of risk-adapted treatment stratification in advanced nasopharyngeal cancer. Dose-reduced radiotherapy (60 Gy) in low-risk patients resulted in a favorable toxicity profile with promising oncological results in a single-arm phase II study. In a phase III study, intensity-modulated radiotherapy alone showed comparable survival to combined radiochemotherapy with cisplatin in selected low-risk patients. In high-risk patients, addition of the EGFR antibody nimotuzumab to definitive radiochemotherapy showed an increased 5­year survival rate compared to placebo (phase III study). Although an immediate change in clinical practice in Europe based on these studies is questionable, the concept of risk-adapted therapy taking into account biological characteristics (Epstein-Barr virus [EBV] DNA level) is future orientated. Similar to previous years, the contributions on recurrent/metastatic salivary gland and thyroid cancer emphasized the importance of targeted therapies based on vulnerable molecular target lesions.

Lipidome Analysis of Oropharyngeal Tumor Tissues Using Nanosecond Infrared Laser (NIRL) Tissue Sampling and Subsequent Mass Spectrometry.

Ultrashort pulse infrared lasers can simultaneously sample and homogenize biological tissue using desorption by impulsive vibrational excitation (DIVE). With growing attention on alterations in lipid metabolism in malignant disease, mass spectrometry (MS)-based lipidomic analysis has become an emerging topic in cancer research. In this pilot study, we investigated the feasibility of tissue sampling with a nanosecond infrared laser (NIRL) for the subsequent lipidomic analysis of oropharyngeal tissues, and its potential to discriminate oropharyngeal squamous cell carcinoma (OPSCC) from non-tumorous oropharyngeal tissue. Eleven fresh frozen oropharyngeal tissue samples were ablated. The produced aerosols were collected by a glass fiber filter, and the lipidomes were analyzed with mass spectrometry. Data was evaluated by principal component analysis and Welch's t-tests. Lipid profiles comprised 13 lipid classes and up to 755 lipid species. We found significant inter- and intrapatient alterations in lipid profiles for tumor and non-tumor samples (p-value < 0.05, two-fold difference). Thus, NIRL tissue sampling with consecutive MS lipidomic analysis is a feasible and promising approach for the differentiation of OPSCC and non-tumorous oropharyngeal tissue and may provide new insights into lipid composition alterations in OPSCC.

Impaired DNA double-strand break repair and effective radiosensitization of HPV-negative HNSCC cell lines through combined inhibition of PARP and Wee1.

Objectives: In head and neck squamous cell carcinoma (HNSCC), tumors negative for Human Papillomavirus (HPV) remain a difficult to treat entity and the morbidity of current multimodal treatment is high. Radiotherapy in combination with molecular targeting could represent suitable, less toxic treatment options especially for cisplatin ineligible patients. Therefore, we tested dual targeting of PARP and the intra-S/G2 checkpoint through Wee1 inhibition for its radiosensitizing capacity in radioresistant HPV-negative HNSCC cells. Materials and methods: Three radioresistant HPV-negative cell lines (HSC4, SAS, UT-SCC-60a) were treated with olaparib, adavosertib and ionizing irradiation. The impact on cell cycle, G2 arrest and replication stress was assessed through flow cytometry after DAPI, phospho-histone H3 and γH2AX staining. Long term cell survival after treatment was determined through colony formation assay and DNA double-strand break (DSB) levels were assessed through quantification of nuclear 53BP1 foci in cell lines and patient-derived HPV± tumor slice cultures. Results: Wee1 and dual targeting induced replication stress but failed to effectively inhibit radiation-induced G2 cell cycle arrest. Single as well as combined inhibition increased radiation sensitivity and residual DSB levels, with the largest effects induced through dual targeting. Dual targeting also enhanced residual DSB levels in patient-derived slice cultures from HPV-negative but not HPV+ HNSCC (5/7 vs. 1/6). Conclusion: We conclude that the combined inhibition of PARP and Wee1 results in enhanced residual DNA damage levels after irradiation and effectively sensitizes radioresistant HPV-negative HNSCC cells. Ex vivo tumor slice cultures may predict the response of individual patients with HPV-negative HNSCC to this dual targeting approach.

A Lack of Effectiveness in the ATM-Orchestrated DNA Damage Response Contributes to the DNA Repair Defect of HPV-Positive Head and Neck Cancer Cells.

Patients with human papillomavirus-positive squamous cell carcinoma of the head and neck (HPV+ HNSCC) have a favorable prognosis compared to those with HPV-negative (HPV-) ones. We have shown previously that HPV+ HNSCC cell lines are characterized by enhanced radiation sensitivity and impaired DNA double-strand break (DSB) repair. Since then, various publications have suggested a defect in homologous recombination (HR) and dysregulated expression of DSB repair proteins as underlying mechanisms, but conclusions were often based on very few cell lines. When comparing the expression levels of suggested proteins and other key repair factors in 6 HPV+ vs. 5 HPV- HNSCC strains, we could not confirm most of the published differences. Furthermore, HPV+ HNSCC strains did not demonstrate enhanced sensitivity towards PARP inhibition, questioning a general HR defect. Interestingly, our expression screen revealed minimal levels of the central DNA damage response kinase ATM in the two most radiosensitive HPV+ strains. We therefore tested whether insufficient ATM activity may contribute to the enhanced cellular radiosensitivity. Irrespective of their ATM expression level, radiosensitive HPV+ HNSCC cells displayed DSB repair kinetics similar to ATM-deficient cells. Upon ATM inhibition, HPV+ cell lines showed only a marginal increase in residual radiation-induced γH2AX foci and induction of G2 cell cycle arrest as compared to HPV- ones. In line with these observations, ATM inhibition sensitized HPV+ HNSCC strains less towards radiation than HPV- strains, resulting in similar levels of sensitivity. Unexpectedly, assessment of the phosphorylation kinetics of the ATM targets KAP-1 and Chk2 as well as ATM autophosphorylation after radiation did not indicate directly compromised ATM activity in HPV-positive cells. Furthermore, ATM inhibition delayed radiation induced DNA end resection in both HPV+ and HPV- cells to a similar extent, further suggesting comparable functionality. In conclusion, DNA repair kinetics and a reduced effectiveness of ATM inhibition clearly point to an impaired ATM-orchestrated DNA damage response in HPV+ HNSCC cells, but since ATM itself is apparently functional, the molecular mechanisms need to be further explored.

[Special tumor entities in the head and neck region : Nasopharyngeal carcinoma, salivary gland, and thyroid cancer]. / Spezielle Tumorentitäten im Kopf-Hals-Bereich : Nasopharynxkarzinom, Speicheldrüsenkarzinom und Schilddrüsenkarzinom.

BACKGROUND: In recent years the number of studies on special tumor entities in the head and neck region has increased. During the 2021 meetings of the American Society of Clinical Oncology (ASMO) and the European Society for Medical Oncology (ESMO), several studies were presented which predict changes in clinical treatment algorithms for nasopharyngeal carcinoma, salivary gland, and thyroid cancer. OBJECTIVE: Future treatment alterations in specific head and neck tumor entities were evaluated after screening clinical studies presented at the 2021 ASCO and ESMO meetings. MATERIALS AND METHODS: A systematic analysis of the phase II and III clinical trials for nasopharyngeal carcinoma, salivary gland, and thyroid cancer treatment presented at ASCO and ESMO 2021 was performed. Taking into account current treatment standards, the results are structured in terms of their potential clinical significance. RESULTS AND CONCLUSION: In curative treatment of advanced nasopharyngeal carcinoma, adjuvant therapy with capecitabine after primary chemoradiation should be discussed as a new standard. In the palliative treatment of nasopharyngeal carcinoma, an increasing role of immunotherapy can be predicted. Recurrent or metastatic salivary gland cancer can often be treated very effectively with targeted substances if molecular target lesions are present. Immunotherapies currently play a subordinate role; they only seem to be effective in a few patients with salivary gland cancer, who cannot currently be reliably identified using predictive markers. Patients with radioiodine-refractory differentiated thyroid cancer benefit from treatment with the multi-tyrosine kinase inhibitor cabozantinib after failure of vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFR-TKI) therapy.

Patient derived ex vivo tissue slice cultures demonstrate a profound DNA double-strand break repair defect in HPV-positive oropharyngeal head and neck cancer.

BACKGROUND: HPV-positive head and neck squamous cell carcinoma of the oropharynx (OPSCC) are more sensitive towards radiation than HPV-negative OPSCC. Two main theories exist regarding the underlying mechanism. Stronger lymphocyte infiltration points to an enhanced immunogenicity, whereas data from HPV-positive HNSCC cell lines suggest an enhanced cellular radiosensitivity based on a defect in DNA double-strand break (DSB) repair. The critical limitation of the latter theory is that the evidence was largely derived from a small number of established HPV-positive HNSCC cell lines. METHODS AND MATERIALS: Fresh patient-derived OPSCC samples were cut in 400 µm sections and cultured on cell culture inserts. Slice cultures were irradiated, in part combined with ATM inhibition, and fixed and frozen after 2 and 24 h. DSBs were analyzed by quantification of 53BP1 foci in nuclei co-stained with the SCC marker p63 via immunofluorescence microscopy. RESULTS: Ex vivo OPSCC tumor slice cultures maintained stable oxygenation and proliferation characteristics for at least 3 days. Areas of p63-positivity in immunofluorescence microscopy matched histologically confirmed tumor cell areas in serial sections, indicating the suitability of p63 as a tumor cell marker. p63-positive nuclei in HPV-positive OPSCC tissues (n = 14) showed profoundly elevated numbers of residual radiation-induced DSBs as compared to those from HPV-negative OPSCC (n = 12) (3 Gy: on average 4.9 vs. 1.2 foci per nucleus; p < 0.0001). Within the HPV-positive subgroup, samples derived from patients with a smoking history of less than 10 pack years demonstrated higher residual DSBs as compared to those derived from patients with 10 or more pack years (3 Gy: on average 6.5 vs. 3.2 foci per nucleus; p = 0.0105). Additional ATM inhibition resulted in a substantial increase in residual foci in all 4 HPV-negative samples tested but strikingly only in 2 out of 11 HPV-positive samples. CONCLUSIONS: In summary, our data provide robust, cell line-independent experimental evidence for an intrinsic DSB repair deficiency in HPV-positive OPSCC, strongly suggesting a meaningful contribution to the enhanced clinical radiosensitivity. The reduced effectiveness of ATM inhibition indicates a defect in the ATM-orchestrated DNA damage response. Lower numbers of residual 53BP1 nuclear foci in the ex vivo assay may identify HPV-positive patients with effective DSB repair who should potentially be excluded from de-intensification approaches.

Kinomic comparison of snap frozen and ex vivo-cultured head and neck tumors.

OBJECTIVES: The use of primary tumor tissue in experimental and pre-clinical cancer research is becoming increasingly important. Especially the use of tissue slice cultures of tumor specimen, so called ex vivo cultures or tumor explants, promises functional analysis under approximate physiological conditions. This includes screening and testing of targeted therapeutics directed against deregulated protein kinases. However, it is unclear if ex vivo cultures indeed represent the in situ situation especially with respect to very sensitive and transient molecular processes such as kinase dependent signaling. We now asked here, if and to what extent ex vivo culturing affects kinase activity. MATERIALS AND METHODS: We analyzed the activity of protein tyrosine kinases (PTK) using functional kinome profiling of either snap frozen or ex vivo-cultured tumor tissue samples of head and neck cancer patients. RESULTS: Although we observed a quantitative decline in overall kinase activity after 24 h or 48 h of ex vivo cultivation, we most importantly noticed that the signaling characteristics were conserved in most samples; approximately two thirds of all ex vivo-cultured samples displayed a signaling pattern which was qualitatively comparable to the parental tumor. We could also demonstrate kinase inhibition by treatment of ex vivo slice cultures with the multi-kinase inhibitor staurosporine, although higher concentrations were needed compared to cell cultures. CONCLUSION: We here demonstrate that the tyrosine kinase dependent signaling is conserved under exvivo culturing conditions in the majority of samples, which highlights the power of this method in experimental and pre-clinical cancer research.

Analyzing tyrosine kinase activity in head and neck cancer by functional kinomics: Identification of hyperactivated Src family kinases as prognostic markers and potential targets.

Signal transduction via protein kinases is of central importance in cancer biology and treatment. However, the clinical success of kinase inhibitors is often hampered by a lack of robust predictive biomarkers, which is also caused by the discrepancy between kinase expression and activity. Therefore, there is a need for functional tests to identify aberrantly activated kinases in individual patients. Here we present a systematic analysis of the tyrosine kinases in head and neck cancer using such a test-functional kinome profiling. We detected increased tyrosine kinase activity in tumors compared with their corresponding normal tissue. Moreover, we identified members of the family of Src kinases (Src family kinases [SFK]) to be aberrantly activated in the majority of the tumors, which was confirmed by additional methods. We could also show that SFK hyperphosphorylation is associated with poor prognosis, while inhibition of SFK impaired cell proliferation, especially in cells with hyperactive SFK. In summary, functional kinome profiling identified SFK to be frequently hyperactivated in head and neck squamous cell carcinoma. SFK may therefore be potential therapeutic targets. These results furthermore demonstrate how functional tests help to increase our understanding of cancer biology and support the expansion of precision oncology.

Phase III study of nivolumab alone or combined with ipilimumab as immunotherapy versus standard of care in resectable head and neck squamous cell carcinoma.

Locally advanced head and neck squamous cell carcinoma (LA-HNSCC) often requires postoperative chemoradiation with high risk of toxicity. Disease-free survival (DFS) after 2 years is approximately 70%. Combining nivolumab (N), a PD-1-inhibitor and ipilimumab (I), a CTLA4- inhibitor, may improve DFS due to antitumor effects of immunotherapy. The IMSTAR-HN study compares neoadjuvant N and N ± I 6 months after adjuvant therapy versus standard therapy as first-line treatment for LA-HNSCC. Eligible patients have treatment-naive LA-HNSCC, Eastern cooperative oncology group performance score (PS) ≤1 and no distant metastasis. 276 patients will be randomized into two arms. Primary endpoint is DFS and secondary endpoint includes locoregional control (LRC) and overall survival (OS). This study is one of the first in HNSCCs implementing immunotherapy in first-line treatment in a curative setting. Clinical Trial Registration: NCT03700905 (ClinicalTrials.gov).

Analyzing expression and phosphorylation of the EGF receptor in HNSCC.

Overexpression of the epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinomas (HNSCC) is considered to cause increased EGFR activity, which adds to tumorigenicity and therapy resistance. Since it is still unclear, whether EGFR expression is indeed associated with increased activity in HNSCC, we analyzed the relationship between EGFR expression and auto-phosphorylation as a surrogate marker for activity. We used a tissue micro array, fresh frozen HNSCC tumor and corresponding normal tissue samples and a large panel of HNSCC cell lines. While we observed substantial overexpression only in approximately 20% of HNSCC, we also observed strong discrepancies between EGFR protein expression and auto-phosphorylation in HNSCC cell lines as well as in tumor specimens using Western blot and SH2-profiling; for the majority of HNSCC EGFR expression therefore seems not to be correlated with EGFR auto-phosphorylation. Blocking of EGFR activity by cetuximab and erlotinib points to increased EGFR activity in samples with increased basal auto-phosphorylation. However, we could also identify cells with low basal phosphorylation but relevant EGFR activity. In summary, our data demonstrate that EGFR expression and activity are not well correlated. Therefore EGFR positivity is no reliable surrogate marker for EGFR activity, arguing the need for alternative biomarkers or functional predictive tests.